Grover Gregory N, Alconcel Steevens N S, Matsumoto Nicholas M, Maynard Heather D
Department of Chemistry and Biochemistry & California NanoSystems Institute, University of California, Los Angeles, 607 Charles E. Young Drive South, Los Angeles, California 90095-1569.
Macromolecules. 2009 Oct 27;42(20):7657-7663. doi: 10.1021/ma901036x.
Herein we report the synthesis of vinyl sulfone end functionalized PEGylated polymers by reversible addition-fragmentation chain transfer (RAFT) polymerization for conjugation to proteins. Poly(ethylene glycol) methyl ether acrylate (PEGA) was polymerized in the presence of 1-phenylethyl dithiobenzoate with 2,2'-azobis(2-methylpropionitrile) as the initiator to generate well-defined polyPEGAs with number-average molecular weights (M(n)) by gel permeation chromatography (GPC) of 6.7 kDa, 11.8 kDa and 16.1 kDa. Post-polymerization, the majority of polymer chains contained the dithioester functional group at the omega chain end, and the polydispersity indexes (PDI) of the polymers ranged from 1.08 to 1.24. The dithioester was subsequently reduced via aminolysis, and the resulting thiol was trapped with a divinyl sulfone in situ to produce semi-telechelic, vinyl sulfone polyPEGAs with efficiencies ranging between 85% and 99%. It was determined that the retention of vinyl sulfone was directly related to reaction time, with the maximum dithioester being transformed into a vinyl sulfone within 30 minutes. Longer reaction times resulted in slow decomposition of the vinyl sulfone end group. The resulting semi-telechelic vinyl sulfone polymers were then conjugated to a protein containing a free cysteine, bovine serum albumin (BSA). Gel electrophoresis demonstrated that the reaction was highly efficient and that conjugates of increasing size were readily prepared. After polymer attachment, the activity of the BSA was 92% of the unmodified biomolecule.
在此，我们报告了通过可逆加成-断裂链转移（RAFT）聚合反应合成用于与蛋白质偶联的乙烯基砜末端官能化聚乙二醇化聚合物。聚（乙二醇）甲基醚丙烯酸酯（PEGA）在1-苯乙基二硫代苯甲酸酯存在下，以2,2'-偶氮二（2-甲基丙腈）为引发剂进行聚合，通过凝胶渗透色谱（GPC）生成数均分子量（M(n)）分别为6.7 kDa、11.8 kDa和16.1 kDa的定义明确的聚PEGA。聚合后，大多数聚合物链在ω链末端含有二硫酯官能团，聚合物的多分散指数（PDI）范围为1.08至1.24。随后通过氨解还原二硫酯，所得硫醇原位用二乙烯基砜捕获，以85%至99%的效率生成半遥爪型乙烯基砜聚PEGA。确定乙烯基砜的保留与反应时间直接相关，在30分钟内最大量的二硫酯转化为乙烯基砜。更长的反应时间导致乙烯基砜端基缓慢分解。然后将所得的半遥爪型乙烯基砜聚合物与含有游离半胱氨酸的蛋白质牛血清白蛋白（BSA）偶联。凝胶电泳表明该反应非常高效，并且易于制备尺寸不断增加的偶联物。聚合物连接后，BSA的活性为未修饰生物分子的92%。
